This is an application for continuation of a program to provide intensive training in modern methods of nephrologic and urologic research to postdoctoral fellows with the M.D. and/or Ph.D. degree. Support for funding of nine training stipends per year is requested. Four stipends per year for "adult" nephrology trainees have been continuously funded since 1978 and have been the core source of support for postdoctoral research training in "adult" nephrology at the Yale University School of Medicine. These stipends have been primarily used to support the training of physician-scientists (M.D. or M.D./Ph.D.). When the training program was started in 1978, the principal area of expertise of the training faculty was limited to renal physiology and pathophysiology. Since that time, we have been successful in recruiting faculty who have established Yale as an international center for the study of the genetics of renal disease and hypertension. The research training opportunities at Yale in transplant nephrology and clinical epidemiology have also been greatly enhanced. Despite this expansion of the size and range of expertise of our training faculty, the number of stipends available for "adult" nephrology trainees has remained constant at 4 per year since 1978. This has limited us to recruiting only two physician-scientist trainees per year in order to guarantee each trainee 2-3 years of research training. During the past project period we have had a striking increase in the applicant pool for the "adult" nephrology fellowship program, with over 100 applicants per year who are U.S. citizens or permanent residents. Accordingly, we now request an increase in funding to support 6 stipends per year for the "adult" nephrology component of the program, which would allow us to recruit three physician-scientist trainees per year to take advantage of the tremendous expansion of nephrology research training opportunities at Yale since 1978. Starting in 1987, one stipend per year was added to the program to support the research training of individuals in pediatric nephrology with a second stipend added in 1995. We request continued funding of two stipends per year for use by pediatric nephrology trainees. Starting in July, 1995, one stipend per year was added to the program to support the research training of individuals in urology. We request continued funding of one stipend per year for use by urologic trainees.